The invention relates generally to a strap connector assembly for use in a manufactured home stabilizing foundation system using tension straps. More particularly, the invention relates to a strap connector assembly which does not create harmful stress concentrations within the tie down straps when the straps are arranged in non-perpendicular orientations with respect to the manufactured home, and which positively latches to the manufactured home frame.
Manufactured homes, such as mobile homes, trailers, prefabricated homes, and the like are manufactured at a central manufacturing site and, upon completion, are moved to a location where they are to be occupied. Because these homes are designed to be easily transported from one site to another, they are not built on permanent foundations but, rather, typically are placed on piers such as concrete blocks, pilings, or stabilizing jacks. Normally, the piers directly support the frame of the manufactured home which typically comprises two or more support beams, such as steel I-beams, to which the home is fixedly secured.
If the manufactured home is not anchored securely in position on its piers, the home can be shifted by strong winds or earth tremors which can cause the home to be forced from its foundation. Due to this risk, various types of stabilizing systems have been used for stabilizing the manufactured homes on their piers in order to keep the homes from shifting in response to wind and/or seismic forces. In one particularly effective system, a plurality of tension straps are used to tether the manufactured home to the ground. In these systems, the tension straps typically extend perpendicularly outwardly from incremental positions along the length of the manufactured home. Usually, the tension straps extend downwardly from the support beams of the manufactured home frame to ground anchors that are deeply embedded into the soil. Often, the tension straps are securely connected to the beams with strap connector assemblies that latch onto the support beams. Normally, a strap connector assembly comprise a metal clamp member that includes a hook which securely grips an upper flange of the support beam. The tension straps usually are threaded through a strap slot formed in the clamp member. These strap slots normally are configured so as to be parallel to the hook and the longitudinal direction of the manufactured home, such that the tension straps can be positioned substantially perpendicularly to the longitudinal direction of the manufactured home.
Although functioning adequately under most circumstances, conventional strap connector assemblies present several drawbacks. Most importantly, these strap connector assemblies do not account for longitudinal shifting of the manufactured home due to wind or seismic forces. When a manufactured home shifts under the influence of such forces, the longitudinal position of the strap connector assemblies, and their respective strap slots, likewise shift in the same longitudinal direction. Because the ground attachment points of the tension straps are fixed by the anchors, the tension straps cannot similarly shift longitudinally, thus causing the orientation of the tension straps to become diagonal with respect to the longitudinal direction of the I-beam of the manufactured home. In that the strap slots of the strap connector assembly cannot reorient themselves to accommodate the diagonal orientations of the straps, torsional stresses are concentrated on the straps at the point where the straps connect to the strap connector assemblies. Such stress concentrations can similarly occur in situations in which the tension straps are improperly installed, e.g. In a non-perpendicular orientation relative to the manufactured home. Large stresses can cause failure of one or more of the tension straps, therefore in order to securely fix the home to the foundation it is important to insure that there are no large stresses in the tension straps. Even if torsional stresses do not cause a failure of a strap, torsional stresses can violate the standards stipulated by the United States Department of Housing and Urban Development (HUD) regarding systems for stabilizing foundations. In addition, a shift of the ground anchor in the longitudinal direction coupled with the tension force in the tension strap induces a torque on the strap connector assembly. Such a torque can cause the strap connector assembly to orientate itself so as to relieve the stress, but in doing so the hook of the strap connector assembly is no longer properly secured to the I-beam.
Sometimes it is necessary or convenient to position the ground anchors 20 such that the tension straps 24 are not orientated perpendicular to the longitudinal direction of the I-beam of the home. For example, there may be an obstruction such as an underground pipe or wires, or a large stone, which can be surmounted if the tension strap could be positioned in a non-perpendicular orientation. From the above, it can be appreciated that it would be desirable to have a strap connector assembly which does not create harmful stress concentrations on the tension strap when the strap is orientated in a non-perpendicular orientation with respect to the home. It would also be desirable to have a strap connector assembly that is easily attached to the home within the standards set by HUD, such that when the strap is inadvertently in a non-perpendicular orientation there are no harmful stresses and the stabilized foundation remains in compliance with HUD standards.
U.S. Pat. No. 5,983,573, discloses a device for relieving torsional stresses in a tension strap used in a stabilizing foundation system. The disclosed device includes a clamp member for hooking onto an I-beam of the home and a swivel member coupled to the clamp member by a bolt or pin. While the product of the ""573 patent functions properly as intended, this two piece product with its connector bolt is more expensive to produce than a one piece product and requires some adjustment at the site of the manufactured home during installation. The present invention, described in more detail herein below, seeks to overcome these problems, while addressing the problem of relieving torsional stress in the tension strap.
Briefly described, the present invention relates to a tension strap connector assembly for use in a stabilizing foundation system for a manufactured home which comprises a frame including at least one flanged support beam. The tension strap connector assembly includes a hook portion adapted to latch about a flange of the manufactured home support beam, a strap slot adapted to receive a tension strap of the stabilizing foundation system, and the tension strap which has one end extending through the strap slot. The strap slot is shaped for altering the orientation of the tension strap relative to the hook portion so that the tension strap can be arranged in non-perpendicular orientations with respect to the lengths of the support beams of the manufactured home without once nor eating torsional stresses within the tension strap.
The strap connector assembly includes a connector plate and a rocket bearing. The connector plate includes a body portion having first and second ends, with a hook portion at the first end and strap mounting extension at the second end. The strap mounting extension extends from the body portion and has an opening extending therethrough. The opening has a convex edge distal from the first end of the body portion and is adapted to receive both the rocker bearing and a tension strap. The rocker bearing is formed from a flat strap into a U-shaped body having a pair of legs joined at one end by a concave bend having a concave inner surface and an outer convex surface. The outer convex surface of the rocker bearing provides a curved, rounded bearing surface for engagement by the tension strap. The inner concave surface of the rocker bearing is rectilinear along the transverse length of the rocker bearing, and is adapted to fit loosely around the convex edge of the opening in the connector plate. Due to the rectilinear transverse length of the concave inner bearing surface of the rocker bearing which is matched with and bears against the curvature of the convex edge of the opening in the connector plate, there is only one transverse point of contact between the concave bearing surface of the rocker bearing and the convex edge of the connector plate. This point of contact shifts as the rocker bearing rocks on the convex edge; similar to how the point of contact between a rocking chair and a floor shifts as the chair is rocked. The load of the tension strap is communicated to the rocker bearing, and from the rocker bearing to the connector plate at the movable point of contact.
An advantage of having the rocker bearing rock on the convex edge, instead of having a pivotably mounted swivel member, is that the rocker bearing and the connector plate do not become frozen together. Even when there is rust formed between the rocker bearing and the connector plate, the rust bond is easily broken because there is only one transverse point of contact between the connector plate and the rocker bearing. Whereas, in a device which uses a pin to couple two pieces together, the entire circumference of the pin can become bonded by rust to the coupled pieces, thereby locking the device into one orientation. Also, the connector plate is formed in one piece instead of multiple pieces pivotally connected by a bolt, or other conventional coupling connectors. In addition, the one piece structure is stronger and less expensive to manufacture.
The objects, features, and advantages of this invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. It is intended that all such additional features and advantages be included therein with the scope of the present invention, as defined by the claims.